Registration Decision for the Residential Use of Spirotetramat

on Citrus

U.S. Environmental Protection Agency

Office of Pesticide Programs

Registration Division

Approved by: _

 Susan Lewis, Director

Registration Division

Date: January 19, 2016
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Registration Decision for Spirotetramat on Citrus Trees Grown in 

Residential Areas, the First Residential Use for the Active Ingredient 

Spirotetramat

Summary

The U.S. Environmental Protection Agency (referred to hereafter as EPA) is 

unconditionally registering a new product containing the active ingredient spirotetramat

under section 3(c)(5) of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). 

The product is for use only on citrus trees grown in residential areas. 

Spirotetramat is currently registered for use on ornamentals (ex. Christmas trees) and

agricultural crops such as bananas, citrus, coffee, hops, pineapple, apples, pears, grapes, 

cherries, peaches, tree nuts, tomatoes, peppers, celery, spinach, lettuce, peas, lentils, 

potatoes, and watercress.

The new product, “14ACP703 SC Insecticide/Miticide,” is a soluble concentrate liquid 

formulation containing 22.4% spirotetramat. The main target pest is Asian citrus psyllid.

The product is intended for use by commercial licensed applicators and the instructions 

for use are based on applications made using commercial equipment (spray tanks with 

agitators). The application rates are expressed in ounces of product per acre, or ounces 

per 100 gallons of water, and not in terms of hose-end sprayers or other types of 

equipment used by the general consumer. 

The application rates and restrictions for this proposed use of spirotetramat on residential 

sites are identical to the currently registered agricultural use on citrus. 

Requested Action

On September 10, 2014, EPA received an application from Bayer Environmental Science

to register a new end-use product containing spirotetramat (CAS Number: 203312-25-1), 

for use on citrus trees grown in residential areas. This action represents the first time 

EPA has considered a residential use involving spirotetramat. Per EPA’s policy to seek 

public comment on key proposed regulatory actions, EPA opened a 30-day public 

comment period on its regulatory position on December 9, 2015.

Evaluation

When evaluating an application for a pesticide registration, the EPA assesses a wide 

variety of exposure information. This includes where and how the pesticide is used, the 

environmental fate (i.e., how the chemical will move in the environment) and toxicity 

studies (i.e., effects on humans and other non-target organisms) to determine the 
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likelihood of adverse effects (i.e., risk) from exposures associated with the proposed use 

of the product. Risk assessments are developed that evaluate the environmental fate of 

the compound, as well as how it might affect a wide range of non-target organisms,

including humans and terrestrial and aquatic wildlife (plants and animals). On the basis 

of these assessments, EPA evaluates and approves language for pesticide labeling to 

ensure the directions for use and safety measures are appropriate to mitigate potential 

risks. In this way, each pesticide’s labeling helps to communicate essential limitations 

and mitigations that are necessary for public safety. It is a FIFRA violation to use a 

pesticide in a manner inconsistent with its labeling. 

1. Assessment of Risk to Human Health

For the use of spirotetramat on citrus trees in residential sites, the database of studies 

required to support the assessment of risk to human health is complete. 

Table 1 summarizes the toxicological endpoints used in the human health risk 

assessment. The acute dietary endpoint is based on clinical signs and decreased motor 

activity observed in the acute neurotoxicity study in rats. The chronic dietary endpoint is

based on the thymus involution in males in the chronic dog study.

Table 1.--Summary of Toxicological Doses and Endpoints for Spirotetramat, for Use 

in Human Health Risk Assessment

Exposure/Scenario Point of Departure and 

Uncertainty/Safety 

Factors

RfD, PAD, 

LOC for Risk 

Assessment

Study and 

Toxicological 

Effects

Acute dietary

(All populations)

NOAEL = 100

mg/kg/day 

UFA = 10x

UFH = 10x

FQPA SF = 1x

Acute RfD = 

1.0 mg/kg/day

Acute 

neurotoxicity 

study – rat 

LOAEL = 200

mg/kg/day 

Chronic dietary 

(All populations)

NOAEL= 5 mg/kg/day 

UFA = 10x

UFH = 10x

FQPA SF = 1x

Chronic RfD = 

0.05 mg/kg/day

cPAD = 0.05

mg/kg/day

1-year oral 

toxicity studydog

LOAEL= 20

mg/kg/day 

Cancer (Oral, 

dermal, inhalation)

Spirotetramat is classified as “not likely to be carcinogenic to 

humans” based on data showing no treatment related increase 

in tumor incidence in rat and mouse carcinogenicity studies. 

Abbreviations: UF = uncertainty factor, UFA = extrapolation from animal to human (interspecies), UFH = potential 

variation in sensitivity among members of the human population (intraspecies), FQPA SF = FQPA Safety Factor, 

NOAEL = no-observed adverse-effect level, LOAEL = lowest-observed adverse-effect level, RfD = reference dose (a = 

acute, c = chronic), PAD = population-adjusted dose, LOC = level of concern.

The evaluation of the chronic toxicity studies indicates that spirotetramat is not 

carcinogenic. EPA has not made a common mechanism of toxicity finding for 

spirotetramat and any other substances. This means that the available information 
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support the conclusion that spirotetramat does not have a common mechanism of toxicity 

with other substances.

The use on citrus trees in residential sites did not require a reassessment of dietary 

exposures since the use pattern is identical to the registered agricultural use pattern, and 

is not expected to result in higher residues. Given the low likelihood of adverse effects on 

humans, more refined estimates of acute and chronic dietary risk were not necessary for 

spirotetramat. The assessment incorporated the highest-level residues on the 

commodities and default or empirical processing factors and conservative drinking water 

estimates of exposure. The dietary assessment also conservatively assumed that 100% of 

every crop was treated. Neither the acute nor the chronic dietary exposure and risk 

estimates exceed the Agency’s level of concern.

EPA aggregates pesticide exposures and risks from three major sources: food, drinking 

water, and residential exposures. When aggregating exposures and risks from various 

sources, EPA considers both the route and duration of exposure.

The acute aggregate risk assessment takes into account exposure estimates from dietary 

consumption of spirotetramat (food and drinking water). The acute dietary exposure 

estimates are not of concern. 

Short-term (1 to 30 day) and intermediate-term (1 to 6 months) aggregate risk 

assessments are necessary for adults since there is potential for handler exposure from the 

residential use of spirotetramat on citrus trees. Since the short-term assessment assumed 

no dissipation (i.e., day-zero residues) for the entire exposure duration (up to 30 days), 

and the short- and intermediate-term points of departure (POD) are the same, the shortterm assessment is expected to be protective of intermediate-term exposure durations. 

For the short-term aggregate risk assessment, potential residential exposures were 

combined with food and drinking water exposures. Specifically, the short-term aggregate 

assessment for adults combines dietary (food + drinking water) exposures with handler 

inhalation exposures resulting from the proposed use.

The short-term residential exposure estimates were aggregated with the chronic dietary 

(food + drinking water) to provide a worst-case estimate of short-term aggregate risk for 

adults. As the short-term aggregate margins of exposure are 1,900 and thus greater than 

100 (the Level of Concern), risk estimates are not exceeded. Short-term aggregate MOEs

are protective of intermediate-term exposure durations. 

For the spirotetramat use on residential citrus trees, there is the potential for dermal 

exposure for adults and children; however, since there is no dermal POD, a quantitative 

assessment of dermal risk is not necessary. Additionally, although applications will be 

made only to the foliage of the trees, the label directs that children and pets be kept off 

treated areas until they are dry. Post-application inhalation exposure is not of concern

due to the combination of low vapor pressure for spirotetramat (1.5 x 10-8 Pa at 25oC) and 

the expected dilution in outdoor air. 
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The new formulation of spirotetramat (“14ACP703 SC Insecticide/Miticide”) has a low 

acute toxicity profile. The acute oral, acute dermal and primary eye irritation studies 

meet the criteria for Toxicity Category III. The acute inhalation and primary dermal 

irritation studies meet the criteria for Category IV. The product is, however, a dermal 

sensitizer, therefore the label includes a statement alerting the user and requires personal 

protective equipment (long-sleeved shirt and long pants and chemical-resistant gloves). 

The signal word for 14ACP703SC is “Caution.”

2. Assessment of Ecological Risk

The use of spirotetramat on citrus trees specifically located on residential plots is 

identical to the use of spirotetramat on citrus in agricultural settings. The single and 

seasonal application rate are the same and the interval between applications is also the 

same. In 2012, EPA conducted an ecological assessment for the agricultural citrus use. 

Given that the use pattern and label restrictions are the same for agricultural citrus and 

residential citrus, a new ecological risk assessment was not conducted. 

Spirotetramat has low volatility and undergoes rapid photochemical degradation. 

Environmental concentrations in air are expected to be minimal and long-range transport 

is unlikely to occur.

Dissipation of spirotetramat in field trials was rapid with a dissipation half-life in a range 

of 0.3 – 1.0 day. Since almost no transfer of spirotetramat in soil layers below 15 cm was 

observed in the submitted studies, and volatility is low, dissipation of spirotetramat is

considered more or less consistent with degradation. No differences were observed

between bare ground and cropped plots. Due to the short half-life in soil, the potential of 

accumulation in soil and carry-over of spirotetramat from one year to the next is 

considered negligible.

For the use of spirotetramat on citrus, the acute and chronic risk to freshwater and 

estuarine/marine fish is below the Agency’s level of concern. The acute and chronic risk 

to freshwater and estuarine/marine invertebrates is also below the level of concern. There 

are no risks of concern for aquatic plants.

Spirotetramat is practically non-toxic to birds and mammals on an acute basis and the risk 

for both is below the Agency’s level of concern. A chronic risk for birds was assessed 

from crops with higher use rates than citrus and represents upper bound exposure 

scenarios. There is no chronic risk concern when using mean exposure values for these 

crops with the higher application rates. The level of concern is exceeded in limited 

circumstances, ie. when birds repeatedly consume food items that are contaminated. The 

chronic risk to mammals is below the level of concern. There is no risk of concern for 

terrestrial plants.
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Spirotetramat has practically no acute toxicity to honey bees through oral or contact 

exposure. Brood feeding studies and semi-field studies have suggested, however, 

potential effects on honey bee brood. EPA has not concluded at this time that 

spirotetramat presents a chronic risk to bees but has addressed the potential risk with 

mitigation through label restrictions.

Alternatives

Spirotetramat targets piercing and sucking insects such as aphids, whiteflies and psyllids. 

The registered alternatives for backyard (ie. residential) citrus include organophosphates 

such as malathion, carbamates such as carbaryl and neonicotinoids such as imidacloprid. 

All of these are acutely toxic to honey bees. The organophosphate and carbamate 

chemical classes generally pose a greater risk to humans than does spirotetramat. Both 

classes are undergoing cumulative risk assessments as required by the Food Quality 

Protection Act.

Benefits

As noted above, spirotetramat is an alternative to older chemistries. It is an important pest 

management tool for the piercing/sucking insect spectrum since many of these pests (e.g. 

whiteflies) tend to develop resistance. Commercial citrus growers have reported that 

spirotetramat has been vital in their struggle against the Asian citrus psyllid (ACP). This 

pest vectors Huanglongbing (HLB), also known as “Citrus Greening,” which is an 

invasive bacterium that is threatening the collapse of the U.S. citrus industry. Infected 

trees cannot recover and growers must destroy them. According to USDA’s “National 

Agricultural Statistics Survey,” 130,108 acres of citrus in Florida were abandoned in 

20151

. In addition to providing protection for citrus trees in non-agricultural settings, the 

proposed use of spirotetramat will target ACP that may be harboring in these trees, 

thereby providing support to commercial citrus growers.

Other serious pests that damage citrus include California red scale, mealybugs and 

whiteflies. Spirotetramat is also effective against these pests. The Insecticide Resistance 

Action Committee (IRAC) has classified spirotetramat in IRAC Group 23 since the

chemical’s mode of action is by inhibition of lipid biosynthesis. With the new product 

registration, spirotetramat is the only insecticide with this mode of action that will be 

available for use on citrus in residential sites. Thus, this use provides a new tool for 

protection of residential citrus trees against serious target pests, especially the Asian 

citrus psyllid.

1http://www.nass.usda.gov/Statistics_by_State/Florida/Publications/Citrus/aban/CitAA15.pd
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Regulatory Decision

The Agency is unconditionally granting the registration of a new product containing the 

active ingredient spirotetramat, “14ACP703 SC Insecticide/Miticide,” under section 

3(c)(5) of FIFRA This is the first use of spirotetramat in residential areas. The use is 

limited to citrus trees.

This product is identical in formulation to the currently registered product Movento®, 

EPA Registration Number 264-1050. The new use pattern on citrus in residential areas 

is identical to the registered agricultural use pattern. 

Spirotetramat does not meet the risk criteria for classification as a Restricted Use 

pesticide. The use of “14ACP703 SC Insecticide/Miticide” on citrus in residential sites, 

however, is labeled for use by commercial licensed applicators and the registrant does not 

intend to sell it for use by the general consumer. The Directions for Use are expressed in 

terms appropriate for commercial applicators, the application instructions are not typical 

for an application of a pesticide by the public who generally do not have access to high 

volume equipment.

Since citrus is attractive to pollinators, applications of spirotetramat are not allowed when 

the trees are in bloom. Honey bees forage for citrus pollen which is fed as bee bread to 

the larval bees (the brood). Removing this exposure route during this time protects the 

colony brood from potential risk. The product label bears the following restriction:

“Do not apply this product within 10 days prior to bloom, during bloom, or until 

petal fall is complete.”

Public Comments

Notice of Receipt

On February 4, 2014, EPA published a Notice of Receipt (NOR) in the Federal Register 

of an application for registration of “14ACP703 SC Insecticide,” a product containing 

22.4% spirotetramat to be used on citrus trees grown in residential areas, and announced 

a public comment period of 30 days. No comments were received in response to the 

NOR.

Proposed Registration Decision

On December 9, 2015, EPA posted the “Proposed Registration Decision for the 

Residential Use of Spirotetramat on Citrus” to the public docket (EPA-HQ-OPP-2014-

0923) and announced a 30-day public comment period. Two comments were received. 

Both comments expressed support for the registration. The comment submitted by the 

Chairman of the Citrus Research Board stated: “The use of this material in the fight 
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against the HLB Bacterium is of the utmost importance in our fight to save the California 

Citrus Industry.”

Regulatory Rationale

Spirotetramat is an alternative to older classes of chemistries currently on the market for 

residential sites, including organophosphates, carbamates, pyrethroids and 

neonicotinoids. The mode of action against the target pests (aphids, scales, leafminers, 

thrips, mealybugs, whiteflies and psyllids) is unique (inhibition of acetyl CoA 

carboxylase). No other insecticide with this mode of action is registered for use against 

pests infesting citrus grown outside of agricultural sites. The registration of spirotetramat

will protect not only citrus trees growing in neighborhoods and other residential sites, but 

as noted above, will also be highly beneficial to commercial growers by targeting 

populations of pests harboring outside of the orchards, especially the Asian citrus psyllid. 

The risk assessments supporting this decision are located in regulatory docket EPA-HQOPP-2014-0923.